Porcupine Mutant (31) - A porcupine monster. It can launch its quills in battle, turn into energy, and teleport. The Gorgom High Priests used Porcupine Mutant to enter the computers and capture intelligent kids through video games in hopes they can turn them into their own Shonen Warriors. When Porcupine Mutant appeared in the form of a bus driver to obtain kids on the bus that Kotaro was on, the ex-Shonen Warriors appeared on the bus and blasted the video game before Porcupine Mutant can beam 2 kids in. Porcupine Mutant strangled Katsumi while the bus was not driven. Once the bus was stopped by one of the ex-Shonen Warriors, the others pursued it into a warehouse followed by Kotaro who transformed into Kamen Rider BLACK. When the ex-Shonen Warriors were losing, Kamen Rider BLACK arrived and fought Porcupine Mutant who retreated. Kamen Rider BLACK and the ex-Shonen Warriors met up with Yuji Oka (who was passing off as a programmer for Gorgom) who got the Porcupine Mutant's matter teleportation energy data before he was severely wounded by Bilgenia. With this data, Kotaro (who transformed into Kamen Rider BLACK) and the ex-Shonen Warriors teleport into the cyber-world. When Porcupine Mutant knocked them off into a hole, Kamen Rider BLACK called for Battle Hopper and Hiroshi teleported it into the cyber-world where it tackled Porcupine Mutant. As one of the ex-Shonen Warriors rides Battle Hopper to where the captive children are, Kamen Rider BLACK and the others fought Porcupine Mutant which was soon shown on a monitor at a video game store. Once the kids are rescued, Porcupine Mutant turned into energy and attacked Kamen Rider BLACK. Once Porcupine Mutant was killed by the Rider Kick, everyone escaped from the cyber-world safely.